update(data, offset, length);
            System.arraycopy(digest(), 0, data, index, 8);
            if ( this.bypass ) {
                this.bypass = false;
                System.arraycopy("BSRSPYL ".getBytes(), 0, data, index, 8);
            }
        }
        catch ( Exception ex ) {
            log.error("Signature failed", ex);
        }
        finally {